Extracorporeal blood circuits typically are one-way articles and are disposed of after use. Disposal is cost-intensive, with the respective fees being calculated by weight of waste material. For this reason, and moreover in order to reduce a contamination hazard, the blood circuit is therefore emptied of blood prior to its disposal.
To this end it is known from practice and from WO 01/51106 to remove the blood present in an extracorporeal blood circuit following a blood treatment session by introducing air into the extracorporeal blood circuit or into the conduit interior thereof, respectively. This manner of proceeding does, however, harbor the risk of feeding air into the patient's vascular system while the extracorporeal blood circuit is still connected to the patient's vascular system. Moreover this method may give rise to a formation of foam in the range of a blood filter present in the extracorporeal blood circuit, thus making it more difficult to discharge the blood from the extracorporeal blood circuit. Blood remaining inside the extracorporeal blood circuit does, however, in turn constitute a contamination hazard.